Method and apparatus for hydraulic reaming of oil wells



Oct. 11, 1955 T. E. QUICK 2,720,381

METHOD AND APPARATUS FOR HYDRAULIC REAMING OF OIL WELLS Filed May 2, 1949 ENTOR. THOYAS QU\CK BY TTORNE United States Patent Ofiiice 2,720,381 Patented Oct. 11, 1955 METHOD AND APPARATUS FOR HYDRAULIC REAMING OF OIL WELLS Thomas E. Quick, Wichita, Kans.

Application May 2, 1949, Serial No. 90,814

4 Claims. (Cl. 255--1.8)

This invention relates in general to a method and apparatus for cleaning oil wells and for the regeneration of oil well productivity, and in particular to an oil well production increasing and cleanout method and means employing the hydraulic principle inherent in a column of liquid exerting a force suflicient to provide a powerful jet for disintegrating temporarily clogged oil bearing stratum below a well casing, and the principle of difierential pressure between a column of liquid and a column of air and liquid for removing the disintegrated debris from the clogged stratum.

The invention is also more specifically directed to what may be termed a hydraulic reamer for oil wells.

When an oil well is drilled and begins producing, the oil is forced through oil bearing stratum and up the casing by the pressure of oil, gas, and water back of the oil reservoirs.

It has been estimated that under normal conditions the production of a well falls below an economical level when only approximately 20% of its potential has been reached. On this basis we can recover only about 20% of the oil which has been discovered, leaving a tremendous potential of 80%, discovered but unrecoverable with present methods.

The primary cause of this loss in productivity is due to the clogging of the pores of sand, limestone or other structure in the immediate vicinity of the casing by the B. S., or basic sediment, as it is called in the field.

This basic sediment varies with the different grades of crude oil. Both asphalt and paraffin base oils produce aggravating basic sediment or paraflin heavy ends, a small percentage of which gravitates out of suspension in the oil and gradually accumulates in the pores of the oil bearing stratum, retarding, and finally stopping, the free flow of crude oil therethrough.

This clogging eifect by basic sediment can be better comprehended by visualizing what is taking place as the crude oil is being forced inwardly to concentrate in a central area. The closer the crude oil approaches the well casing the greater is the concentration of crude oil in relation to the porosity of the oil bearing stratum and consequently the greater the deposit of basic sediment until the immediate area below the casing is reached where crude oil concentration is greatest and deposit of basic sediment is greatest. Here, a hard crust is formed, and oil penetration is constantly diminishing.

In addition to clogging by basic sediment, the mud used when a well is drilled contributes toward retarding the free flow of the crude oil, the mud, basic sediment and other foreign matter and heavy ends slowly but effectively forming a hard crust in the oil bearing stratum immediately surrounding the well below the casing. This crust, as it grows in thickness and area, gradually builds up sutficient resistance to the forces behind the oil reservoirs to render the well sterile; its production either completely stopped or so low that it is economically unsound to continue pumping.

The answer to the problem of loss of production is to isolate and remove the cause, which, as heretofore explained is usually the formation of a hard crust and the impregnating and filling up of the pores of the oil bearing area in the vicinity of the well casing.

In the past, many dilferent methods, processes and structures have been employed to solve this problem. Heat, solvents, liquids and air under pressure have been employed with varying degrees of success.

It is therefore one object of this invention to advance the art further by providing a method and apparatus which will offer simple and positive means whereby loW or non-productive wells can be revived.

It is another object of the invention to provide a method for reviving low or non-productive oil wells, employing two pressure columns, a differential in pressure between the columns, the high pressure column extending from the surface to below the casing and adapted to direct a stream of liquid against the oil bearing area surrounding the well to disintegrate the. basic sediment, sand, mud, etc, the low pressure column extending from the area below the casing to the surface and adapted to receive the disintegrated debris carried by the liquid discharged from the high pressure column.

It is still another object of the invention to provide a supply of air through a separate conduit to the area below the casing to displace the liquid discharged into said area and to maintain said discharged liquid at a level below the hydraulic jet so as not to interfere with the hydraulic action of said jet.

And another object of the invention is to provide a supply of air to the area below the casing, the air in seek ing to escape from the area forming a rising low pressure column to the top of the well, carrying with it discharged liquid and disintegrated debris.

It is another object of the invention to provide a hydraulic jet to disintegrate the crust formed on the oil bearing stratum, a supply of air under pressure to maintain the level of the discharged liquid below the hydraulic jet, and to provide a discharge opening below the level of the hydraulic jet for the removal of the discharged liquid, the air and the disintegrated debris.

And it is still another object of my invention to provide a high pressure hydraulic jet which can be rotated through 360 to clear a large circular area at the lower end of the well, below the casing.

It is also one object of this invention to provide a high pressure hydraulic jet which can be raised and lowered with respect to the casing to increase the vertical size of the cleared area, the jet always remaining above the discharge opening leading from the area being reamed to the surface.

Other objects and advantages, as well as the construction and operation of my invention and the method employed will be better understood by reference to the following description in connection with the accompanying drawing in which:

Fig. l is a vertical, cross sectional view through a well employing my hydraulic reamer and method, parts being shown diagrammatically and in elevation.

Fig. 2 is a sectional view on the line 2-2 of Fig. l. a Fig. 3 is a reduced, fragmentary, sectional view at the lower end of the well showing another stage in the cleaning out process.

Fig. 4 is a cross sectional view similar to Fig. 2 of a modified form of my invention.

Referring now to the drawing by numerals of reference 1 designates a well casing extending from a suitable casing head 2 above the surface, through the rock stratum 3 to the oil bearing stratum 4.

Internally positioned at the lower end of the casing 1 and telescopically related thereto is the hydraulic reamer jet tube 5, suitably sealed at its upper end with respect 3 to the casing 1 by a sealing ring 6 and high pressure sealing'memberfl.

A suitable bail 8 may be secured to the upper end of the jet tube and extends to the surface where it is suitably arranged in a manner 'well known -to the art for vertical adjustment of the jet-tube 5.

A single -jet outlet 9 is provided in the {lower .end of the jet tube *5 and is preferably arranged to direct the liquid discharging therefrom at right angles :to the jet tube. The siie'of theputlet or orifice'9 is to be proportionate to the column of liquid being forced therethrough to provide the necessary force '10 the stream of liquid discharging from said outlet for proper disintegration Ofthe ;crust on the oil bearing stratum.

Thelower end of the reamerjettube 5*hasa reduced opening 10 through which passes-low pressure discharge or outlet conduit 11, preferably fixed at its upperendin vertical relation to the casing 1 and concentric-therewith. A suitable high pressure seal 12 may 'be provided between'the reamerfjettube 5 and'the discharge conduit'll.

[The lower end of the discharge conduit llis provided with a-bridged opening 13, the bridge 14 aiding in p reventing complete closure of the opening.

A stop ring 15"is positioned on the dischargeconduit 11 just above the opening :13 and limits the downward movement of the ,telescopicjet tube'5, providing means for preventingthe tube v5 from dropping oil theend of the discharge conduit 11.

Change of direction in ,a horizontal plane of thejetof liquid issuing from the ontlet 9 may be accomplished H by simultaneously rotating the casing 1 and the outletconduit 11, the telescopic tube 5 followingthe movements at said casing and outletconduit.

1111 the modification showninFig. 4, the lower end of the discharge. conduit 11 may be slightly flattened on one or two sides and the reduced opening 101 in thetelescopic jet tube '5 may be shaped tofit the. flattened portions 11' ofthe discharge conduit 11. .This arrangementwill provide an alternate means for rotating the jet ofjliqnid discharging 7 from the jet tube 5 by rotation, only i of the outlet conduit v11.

.A- PPPly f r nd pres ur t p ori ed t thei re being-roamed, the conduit 16, connected above ground to a suitable aircompressor 17, diagrammatically shown, and terminatingin,ajetlS adjacent the opening 13.

Theair conduit :16 is preferably located on the interior of conduit ll at least for a p ort,ion of its lower ,ext fii lily in order that telescopic j et tube;,5 ,vyill clear saidaconduit.

installation and operation "Th i s al at on, h ap ar us t whi m m thq i ct iplq s r la e S m le W t 1 n ..a r d .inip aseen h .pi mpia eq ipmen r m ve th discharge conduit 11 with thetelescopic jet J be S atthe end thereof is lowered until the desired depth is reached.

l qu 19 w ig ma ,b W te o a su i i s p l e t th sa i z an l hou t a a u r s i gie sh ul b bu l 1 11 ,b th W h o h ql m of liquid in the casing, auxiliary pressure, boosting means s h spum m bas n lo sd- Com r se a 'i rse' i t t ea ea be the [W casing will normally seek a level a bove the liquid, and sufl'icient air will he suppliedto keep the liquid rleyel at apq nts os to h tlst,q nin 13. .T or e -t i a the-pre ur of th liqu plu t rrovi n conduit'll'provides an escape outlet for the discharged liquid, disintegrated debris and air.

The provision and control of the air supply provides an automatic means forcontrolling the;dischalrge-flow of liquid; from the well and also proyides a determinant-for the status of'the hydraulic reaming operation. If air pressure in thearea belowthe casing drop s, 'the liquid level will rise decreasing the area availablefor the volume 'of air. -:Continued. pumping..-of air willaincrease the pressure. and volume. and the' liquid will be forced: out

discharge conduit 11 along with a certain quantity of air. This .balance .between the air and the liquid is maintained as the discharged liquid and debris is checked at the top of the well for volume and debris content.

In normal operation it is estimated that the relation between volume of air and volume of liquid will be such as to maintain about 75% airand 25% liquid in the discharge conduit 11 therebyproviding steady circulation.

W n i i f nd a inq as d wql nls Q ai .i .e. y to ain ast ady owo idi shars liquid and the basic sediment content of the discharged liquid has changed to a clear' content of disintegrate'd oil bearing Stratum, than i s reasanable t a m Jha th hard crust, which has clogged :the aiea below the well casing and which has kept the oil from flowing, has been disintegrated and air is escaping through the pores of the oil bearing stratum. The reaming operation can be stopped and the reaming apparatus removed, and the pumping equipment restored to operating position.

The stream of liquid discharging from the jet, after striking the wall of the oil Bbearing stratum and tearing away at the crust-thereonwill-be forced downwardly and inwardly toward the discharge conduit 11 -by the pressure of the airat the upper portion of the area being reamed, and the passage of the'liquidagainst the wall will aidin the disintegration of-said wall. I

As the telescopic jet ;tube 5 is rotated -the hydraulic jet issuing from outlet 9 will disintegrate a circular area concentric with and below the Well casing. Afte'ra 360 revolution,'the rotation of the jet may be continued on the samelevel or it may be-raise'd' oi-lowered at desired increments to increase the vertical dimension of the reamed area. i v

The larger the reamed area the more oil producing stratum is exposed tothe casing and the greater-will be the free flow porous area. Therefore the oil will ilow for a longer period andmore rapid rate 'b'eforethe'basic sediment and encru'sting will again seal thelpores of the oil bearing stratum and stop pr'oductionf "Sufficient pressure can be-obtained on theliqu'id column to liydraulically ream an area of at least tea feet in diameterf A larger diametricarea may not be desirable'because of the possibility of cave-ins. x i i My method 'basically, therefore, will consist in directingv a horizontal hydraulic 'jet under high pressure against the encrusted oil bearing stratum below the'lwell casing, forcing air under pressu roin to 'the"area' -being reamed to hold the level of the dischargedliquid below and clear of the hydraulic jet and forcing th air, liquid and disintegrated debris out -to the surface'of thje'well through agseparate conduit.

My method further includes the raising or lowering of the horiz ontal jet and also its rotation about 36 0iin a horizontal plane. i I i I i i My method and apparatus are to be employed whenthe oil bearingstratum at the lowerend of nine well casing'is elogged 'with basic sediment, such as' asphalt, "paraffin, mud, etc., and production of th'e'well is lower thamdesiredpr has decreasedto a point where i tbecomesnnprofitable to continue, furthenpurnping. Hydraulic reaming by my method and with my apparatus will'jemove-the basic sediment and fother flow restricting materials, :and the normal pressurebaek of the crude oil will be suffic'ient to again start cil fiowtowardt'he well casing." This process maybe" repeated each tith productioK-falls'ofi and int his way itis believed that as'mueh" as 7 O to of the oil potential can 'be rec overed'instead of o'nlythe gor -25%. which is now bein'g obtained? ,With the many' methodsand deyice's-whichhave been devisedyat present, when a welllbecomes -a low'or 'nonproducer if is givenup andabandoned. With my.rnethod and apparatus these dead-and abandoned-fields:caiiabereceived atvery little expense ancl. can be madeiproductive again. It is sometimes .the practice,- whemprodilction of a well falls to a low level to drilltan Qffsetwelhtoflapghe unrecovered reserve. This is far more expensive and time-consuming than hydraulic reaming and reviving the oil well. Offset wells often lack the necessary pressure to satisfactorily clean out mud and debris. My invention will be useful for the initial cleaning out of such offset wells,

It is obvious that changes in form, proportion and details of construction may be resorted to without departing from the spirit of my invention and I reserve all rights to such changes as come within the spirit of these specifications and the claims which follow.

What I claim as new and desire to secure by Letters Patent is:

1. An apparatus for the hydraulic reaming of oil wells for increasing the production thereof, a plurality of conduits including the well casing between the surface of the well and the area below the well casing, hydraulic jet tube carried at the lower end of the casin and rotatably and vertically adjustable thereto, a jet orifice adjacent the lower end of said tube, liquid under pressure passing downwardly through the well casing and the hydraulic jet tube providing a hydraulic jet discharging from the jet orifice against the oil bearing stratum, air under pres sure forced downwardly through another conduit and maintaining the discharged liquid at a level below the hydraulic jet, the third conduit forming an unobstructed high velocity air lift receiving the discharged liquid, disintegrated debris, and air for return to the surface of the well and sealing means between said conduits and the hydraulic jet tube.

2. A method of hydraulic reaming of oil wells for increasing the production thereof which comprises the employment of the existing well casing as a conduit and the directing of a column of liquid downwardly therethrough and discharging a hydraulic jet of the liquid against the oil bearing stratum to remove encrusted oil retarding debris therefrom, changing the position of the hydraulic jet vertically to clear the desired vertical area, supplying a continuous supply of air under pressure through a separate conduit to the area below the well casing suflicient to maintain the level of the discharged liquid below the level of the hydraulic jet and to provide a high velocity air lift for returning the discharged liquid carrying disintegrated debris and air to the surface of the well through an inner unobstructed casing within the well casing.

3. A method of hydraulic reaming of oil wells for increasing the production thereof which comprises the employment of the existing well casing as a conduit for and directing of a column of liquid downwardly therethrough and discharging a hydraulic jet of the liquid against the oil bearing stratum to remove encrusted oil retarding debris therefrom, changing the horizontal direction and vertical position of the hydraulic jet to clear the desired area, supplying air under pressure through a separate conduit to the area below the well casing sufiicient to maintain the level of the discharged liquid below the level of the hydraulic jet and to provide a high velocity air lift for returning the discharged liquid carrying disintegrated debris, and air to the surface of the well through an inner unobstructed casing within the well casing.

4. A method of hydraulic reaming of oil wells for increasing the production thereof which comprises the employment of the existing well casing as a conduit for and directing of a column of liquid downwardly therethrough and discharging a hydraulic jet of the liquid against the oil bearing stratum to remove encrusted oil retarding debris therefrom, changing the direction of the hydraulic jet through a circular path of 360 at desired increments of vertical adjustment to clear the desired area, supplying air under pressure through a separate conduit to the area below the well casing sufiicient to maintain the level of the discharged liquid below the level of the hydraulic jet and to provide a high velocity air lift for returning the discharged liquid carrying disintegrated debris and air to the surface of the well through an inner unobstructed casing within the well casing.

References Cited in the file of this patent UNITED STATES PATENTS 671,429 Bacon Apr. 9, 1901 1,636,455 Blumenberg, Jr. July 19, 1927 1,776,889 Claytor Sept. 30, 1930 1,960,932 Tracy May 29, 1934 2,251,916 Cross Aug. 12, 1941 FOREIGN PATENTS 182,042 Germany Mar. 7, 1907 208,335 Germany Mar. 23, 1909 

